INTRODUCTION

Men who have sex with men (MSM) continue to represent the group with the highest incidence of HIV in the United States, accounting for 61% of all new HIV infections and 79% of new infections amongst men [1]. As aptly depicted in the chapter ‘Special Populations and Public Health Aspects’, there are many risk factors that increase vulnerability of MSM to HIV infection. In line with the sexual minority stress model, MSM face greater rates of stigma, discrimination, violence, social rejection and societal pressures (i.e. related to masculinization, legal issues), which fosters developmental challenges in establishing a sexual minority identity [2]. There is evidence that minority stress may contribute to psychological impairment through maladaptive coping, emotion dysregulation, interpersonal difficulties (i.e. social isolation) and maladaptive cognitions related to one’s self and future [3, 4], which may present further risks for developing psychiatric disorders that contribute to HIV risk and poor HIV-related self-care [2].

As highlighted in this chapter, there is a disparity in rates of psychiatric disorders and psychosocial stressors amongst MSM, most notably depression, substance use disorders and elevated rates of trauma, including childhood sexual abuse (CSA), interpersonal violence and other forms of trauma that may place MSM at greater risk for risky sexual behaviour and subsequent HIV infection. MSM may be particularly vulnerable to these mental health challenges. In fact, there is good evidence to suggest that these co-occurring mental health challenges mentioned above combine and interact to significantly increase the likelihood of MSM engaging in HIV sexual risk behaviour and thereby increase their risk for HIV infection [5, 6]. Although not specific to MSM, this theme is touched upon in the discussion on the ‘intertwined vulnerability’ for multiple mental health problems and HIV infection. Overlapping syndemic factors are an important consideration for MSM, as evidence has demonstrated that syndemic conditions have a synergistic effect on HIV risk; for instance, the co-occurrence of three or more psychosocial risk factors (i.e. depression, substance use, CSA and partner violence) has been shown to increase the likelihood of sexual risk for HIV and HIV infection by almost four times [5]. There may also be nonlinear effects of syndemic factors on HIV risk to consider (e.g. in the relationship between depression and sexual risk) [7], suggesting that moderate levels of depression (rather than high or low depression) may be particularly associated with sexual risk amongst MSM. Finally, it is also important to note that the overlapping factors that increase HIV risk amongst MSM also potentiate HIV transmission amongst those who are infected.